Updrift Erosion of a Barrier-Spit Terminus—Reasons and Morphological Consequences

Abstract

The evolution of the barrier-spit terminus of Skallingen was analyzed on navigational charts and aerial photographs. Between 1654 and 1905, the barrier spit Skallingen built up from a nonvegetated dry sandy ridge to exhibit extensive aeolian dune ridges. After 1910, the barrier-spit terminus slowly started to erode and, between 1945 and 2000, barrier-spit terminus eroded almost 2 km toward the northwest, in the opposite direction of the littoral drift. Cut-off of the sediment bypassing and dredging of the tidal channel is found to be the main reason for erosion of the barrier-spit terminus. Storms have affected the west coast of Skallingen and its barrier-spit terminus very differently, as most erosion at the terminus took place before 1981 and erosion on the west coast mostly took place after 1981. Contemporary with the erosion, a flood tidal delta appeared and it has migrated 1740 m since 1974. The front of the flood tidal delta has increased in height and is close to mean high water spring, and about 380,000 m3 of sediment was deposited within this flood tidal delta east of Skallingen between 1990 and 1999.